LOS ANGELES -- (BUSINESS WIRE) -- CytRx Corporation (NASDAQ: CYTR), a biopharmaceutical research and development company specializing in oncology, today reported positive results from additional statistical analyses that further support the previously announced highly positive top-line efficacy results from a multicenter, randomized, open-label global Phase 2b clinical trial investigating the efficacy and safety of aldoxorubicin compared with doxorubicin as first-line therapy in subjects with metastatic, locally advanced or unresectable soft tissue sarcomas (STS).
Additional analysis determined hazard ratios for the primary endpoint of progression-free survival (PFS) by both investigators at study sites and by a blinded radiology review performed at an independent central laboratory. The hazard ratio for investigator-read scans is 0.37 (95% confidence interval, range of 0.212 to 0.643) (p=0.0004), reflecting a 63% reduction in the risk of disease progression; and the hazard ratio for central lab scans is 0.59 (95% confidence interval, range of 0.36 to 0.96) (p=0.034), reflecting a 41% reduction in the risk of disease progression. Hazard ratios – the likelihood that the study endpoint (in this case tumor progression) will be reached during a given period – are an important measure of the reliability and uniformity of the absolute data for PFS, as presented below. Hazard ratios where the upper limit is less than 1 indicate that there is a significant difference between the two study groups.
CytRx also reported that a Kaplan-Meier analysis of the trial results, which describes the time it takes for tumors to progress in individual patients, showed significant improvement in subjects treated with aldoxorubicin versus subjects treated with doxorubicin. CytRx expects to present full study results for this clinical trial at the American Society for Clinical Oncology (ASCO) Meeting in June, 2014 in Chicago, Illinois.
CytRx President and CEO Steven A. Kriegsman commented, “Because of the tremendous potential for aldoxorubicin to treat soft tissue sarcomas and other common cancers, it is important that we present the initial trial analyses in a timely manner. We are very pleased that additional statistical analyses strongly support the earlier top-line results, which reinforces our confidence in the ability of our linker technology to target the release of doxorubicin directly at the site of cancer.”
As initially reported on December 11, 2013, both the investigator assessment and central lab review showed subjects treated with aldoxorubicin demonstrated highly statistically significant better clinical outcomes than those receiving standard doxorubicin therapy for STS. Specifically, both assessments showed an unambiguous 80% to 100% improvement in PFS among patients treated with aldoxorubicin.
In an intent-to-treat analysis, the investigator-assessed median PFS was 8.4 months for aldoxorubicin patients versus 4.7 months for doxorubicin patients (p=0.0002), while the blinded central lab review indicated that median PFS for aldoxorubicin patients was 5.7 months versus 2.8 months for doxorubicin patients (p=0.018). Per investigators, 67.1% of aldoxorubicin patients had not progressed at 6 months, compared with 36.1% of doxorubicin-treated patients (p=0.005). By blinded central lab review, 46.8% of aldoxorubicin patients had not progressed at 6 months, compared with 23.7% of doxorubicin patients (p=0.038).
About the Global Phase 2b Clinical Trial Design
The study examined 123 subjects who received either aldoxorubicin or doxorubicin in a 2:1 randomization, respectively. Aldoxorubicin was administered to 83 subjects at a dosage of 350 mg/m2 (doxorubicin equivalents of 260 mg/m2) as a 30-minute intravenous infusion on Day 1 of each cycle, while doxorubicin (75 mg/m2) was administered to 40 subjects as a 5-30 minute infusion on Day 1 of each cycle. A cycle of therapy was defined as a 3-week (21-day) period. Multiple cycles were administered until the subject was withdrawn from therapy or until a maximum of 6 cycles were administered. CT scans were obtained every 6 weeks to assess tumor response and progression, and adverse events were collected in a case report form.
About Soft Tissue Sarcoma
STS is a cancer occurring in muscle, fat, blood vessels, tendons, fibrous tissues and connective tissue, and can arise anywhere in the body at any age. According to the American Cancer Society, there are approximately 50 types of STS; and in 2013 more than 11,400 new cases will be diagnosed in the U.S., and approximately 4,400 Americans will die from STS. In addition, approximately 40,000 new cases and 13,000 deaths in the U.S. and Europe are part of a growing underserved market.
The widely used chemotherapeutic agent doxorubicin is delivered systemically and is highly toxic, which limits its dose to a level below its maximum therapeutic benefit. Doxorubicin also is associated with many side effects, especially the potential for damage to heart muscle at cumulative doses greater than 500 mg/m2. Aldoxorubicin combines doxorubicin with a novel single-molecule linker that binds directly and specifically to circulating albumin, the most plentiful protein in the bloodstream. Protein-hungry tumors concentrate albumin, thus increasing the delivery of the linker molecule with the attached doxorubicin to tumor sites. In the acidic environment of the tumor, but not the neutral environment of healthy tissues, doxorubicin is released. This allows for greater doses (3 ½ to 4 times) of doxorubicin to be administered while reducing its toxic side effects. In studies thus far there has been no evidence of clinically significant effects of aldoxorubicin on heart muscle, even at cumulative doses of drug well in excess of 2 g/m2.
About CytRx Corporation
CytRx Corporation is a biopharmaceutical research and development company specializing in oncology. CytRx currently is focused on the clinical development of aldoxorubicin (formerly known as INNO-206), its improved version of the widely used chemotherapeutic agent doxorubicin. CytRx has completed a global Phase 2b clinical trial with aldoxorubicin as a first-line therapy for soft tissue sarcomas, a Phase 1b/2 clinical trial primarily in the same indication, a Phase 1b study of aldoxorubicin in combination with doxorubicin in subjects with advanced solid tumors and a Phase 1b pharmacokinetics clinical trial in subjects with metastatic solid tumors. CytRx plans to initiate under a special protocol assessment a pivotal Phase 3 global trial with aldoxorubicin as a therapy for subjects with soft tissue sarcomas whose tumors have progressed following treatment with chemotherapy. CytRx has initiated a Phase 2 clinical trial with aldoxorubicin in subjects with late-stage glioblastoma (brain cancer), and plans to initiate a Phase 2 clinical trial in HIV-related Kaposi’s sarcoma. CytRx plans to expand its pipeline of oncology candidates based on a linker platform technology that can be utilized with multiple chemotherapeutic agents and may allow for greater concentration of drug at tumor sites. CytRx also has rights to two additional drug candidates, tamibarotene and bafetinib. CytRx completed its evaluation of bafetinib in the ENABLE Phase 2 clinical trial in high-risk B-cell chronic lymphocytic leukemia (B-CLL), and plans to seek a partner for further development of bafetinib. For more information about CytRx Corporation, visit www.cytrx.com.
This press release contains forward-looking statements within the meaning of Section 21E of the Securities Exchange Act of 1934, as amended. Such statements involve risks and uncertainties that could cause actual events or results to differ materially from the events or results described in the forward-looking statements, including risks relating to the outcome, timing and results of CytRx's clinical trials, the risk that the results of any future human testing of aldoxorubicin, including the final data from the Phase 2b clinical testing of aldoxorubicin as a first-line treatment in patients with metastatic, locally advanced or unresectable soft tissue sarcomas who have not been previously treated with any chemotherapy, might not produce objective response or safety results similar to the data described in this press release, risks related to CytRx's ability to manufacture its drug candidates in a timely fashion, cost-effectively or in commercial quantities in compliance with stringent regulatory requirements, risks related to CytRx's need for additional capital or strategic partnerships to fund its ongoing working capital needs and development efforts, including the Phase 3 clinical development of aldoxorubicin, and the risks and uncertainties described in the most recent annual and quarterly reports filed by CytRx with the Securities and Exchange Commission and current reports filed since the date of CytRx's most recent annual report. All forward-looking statements are based upon information available to CytRx on the date the statements are first published. CytRx undertakes no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.